Hello...and fuel mileage wow!

[quaudi]

Most posts are giving mpg for a 5 speed. An automatic will get lower mpg in city driving than a 5 speed. My 02 P5 automatic usually gets 22-26 mpg for city driving, I live in a small city. It did about the same when I purchased it new. The only time I have gone over 400 miles on a tank was on highway trips.

On extended trips (NC-CO and WA) I get 30-34 depending on speed and altitude. 75 mph hurts fuel mpg and so does ethanol fuel. Higher altitudes will normally help mpg.

Before doing anything I would take the car on a highway trip long enough to use a tank of fuel. If you are getting 29-32 mpg it's probably normal. The automatic car turns around 3k rpm at around 67-68 mph. It's shifting pattern is programed for performance rather than high mpg. In city driving where speeds are less than 35-40 the transmission torque converter isn't locked up and that hurts mpg. Frequent changes in speed also prevents the torque converter from locking up.

In short, there is usually a penalty in mpg when moving from a stick shift to an automatic.

Clifton

This is exactly the situation we are in. The wife uses the car primarily for really short daily drives to work with several traffic lights and probably never sees 40 mph. We are switching cars this week because my job involves long drives at highway speeds. This should give us a better read on what the car is doing. We both really like the car. Finding a well cared for, low mileage at a good price example was lucky.

Thanks all for your input and advice.

 

[RockerPro5]

My wife has been driving ours lately, and she doesn't even get 20mpg. That's because all of her (round) trips are really, really short, at low speed, on city streets. Pick up the kids at school, total distance, maybe 1 mile. Drive to the store and back, 1.5 miles. Take a kid to the Doctor, 2 miles. She does try to chain her trips together, but nothing can change the fact that most of her destinations are really close to home, and the car spends most of its time running cold and open loop.

The short trips/stop and go definitely don't help since the engine needs a few miles to reach operating temps to burn fuel properly.

Some tips based on my experience:
Try using good quality 87 octane (http://www.toptiergas.com/retailers.html), on a stock engine, I find I get good mileage with regular gas, as opposed to higher octanes.
If the car sees lots of city driving, try to take it on a nice highway run (if possible) to burn off some carbon. Once in a while I'll let the engine visit the rev limiter (~6500 RPM) and watch the carbon blow out (lol2)

When I used the local grocery store gas station, I would get ~24mpg. Using Petro-Canada gas I got ~28 in winter.

 

[stdntDrvr]

my p5 had crappy mileage similar to what you are seeing...the more mods i did to free up the intake/exhaust, the better my gas mileage was...it got up to 32mpg before it was traded in.

 

[imola.zhp]

I don't usually see 300 miles on a tank, but I don't drive it until its empty either...

Driving style has the most effect on mileage, in my BMW, there is a guage for instant economy, if I drive "efficiently" I can squeeze nearly 30 MPG from the 235hp I6 6-speed in mixed (50% city, 50% hwy) driving, and she requires 91+ octane. If I try to drive that way in the P5, however, it would take FOREVER to get anywhere, lol.

 

[bazooka joe]

sorry, don't know what to tell you.(hand)..i get on avg 26 mpg and i'm a boosted auto to boot!

 

[u812many73]

average mileage per tank for me is right around 360-380
i drive normal, shifting at like 3k maybe a little higher....and ethanol has nothing to do with bad gas mileage, if anything it should increase ur mileage

Your ethanol info is a little backward there.... Ever since Florida has switched to primarily E10, I have lost around 1-2 MPG. That being said, I see an average of 25-27 MPG around town if I am shifting a little higher, 4000 RPM or so. If I completely baby the car, shifting between 2500-3000, I can get as good as 31-32 around town. My best on highway mileage was 34. That's with cruise set at 70. All of this at sea level, the car has never left Florida... sadly.

My guess is that your poor mileage is mostly due to the short stop and go drives your wife is taking. I'm sure once you use a tank like you planned you will see better mileage. If id doesn't change much, I like the idea of checking to see if your rear brakes are hanging as well. They have an odd adjustment screw that if it's even 1/4 turn too tight they will be dragging. If they have been changed in the past and it was by someone who wasn't familiar I could easily see them adjusting it too tight.

 

[flash75]

The American Coalition for Ethanol even admits that fuel consumption increases for most vehicles with the use of E10.

http://www.ethanol.org/pdf/contentmgmt/ACEFuelEconomyStudy_001.pdf

Clifton

 

[hornsfan10609]

and the car spends most of its time running cold and open loop.

I don't know if my car is weird or what, but around here where it isn't cold except in late fall and winter my car warms up to operating temp after about 1 mile of driving. Doesn't matter how long it's been sitting, once I pull onto the main road and drive about 50-55 mph I can watch the temp gauge quickly rise to about the middle, so my car isn't in open loop but for a couple minutes and I bet most others are the same way. Also, our cars and all others that aren't designed to run on ethanol get worse mileage with it. If your car is tuned for it you can pick up hp and tq because of the higher octane, but without proper tuning and sometimes a higher pressure fuel pump ethanol in your gas yields less power and mileage.

 

[slavrenz]

The American Coalition for Ethanol even admits that fuel consumption increases for most vehicles with the use of E10.

http://www.ethanol.org/pdf/contentmgmt/ACEFuelEconomyStudy_001.pdf

Clifton

"The three vehicles averaged 1.5% lower mileage with E10, 2.2% lower mileage with E20, 5.1%
lower mileage with E30, and miles per gallon actually increased by an average of 1.7% when using
E10AK made with the specially denatured ethanol."

Considering E10AK is not normally available anywhere, it seems to me as if that study had exactly the opposite finding of what you state.

 

[slavrenz]

My wife has been driving ours lately, and she doesn't even get 20mpg. That's because all of her (round) trips are really, really short, at low speed, on city streets. Pick up the kids at school, total distance, maybe 1 mile. Drive to the store and back, 1.5 miles. Take a kid to the Doctor, 2 miles. She does try to chain her trips together, but nothing can change the fact that most of her destinations are really close to home, and the car spends most of its time running cold and open loop.

I don't mean to condescend or assume anything about where you live, but couldn't you just walk for most of those trips, rather than drive?

 

[drgnzadiel101]

i get roughly 25-27 miles per gallon here in florida. i always thought these were better on gas


but yea check your o2s

 

[u812many73]

"The three vehicles averaged 1.5% lower mileage with E10, 2.2% lower mileage with E20, 5.1%
lower mileage with E30, and miles per gallon actually increased by an average of 1.7% when using
E10AK made with the specially denatured ethanol."

Considering E10AK is not normally available anywhere, it seems to me as if that study had exactly the opposite finding of what you state.

No he stated it correctly..... He said consumption increased with ethanol, as in using more fuel, meaning the fuel economy went down.

 

[slavrenz]

No he stated it correctly..... He said consumption increased with ethanol, as in using more fuel, meaning the fuel economy went down.

Haha...I'm dumb (headbang)

 

[pasadena_commut]

I don't mean to condescend or assume anything about where you live, but couldn't you just walk for most of those trips, rather than drive?

Sure, if just getting your body there and back was the only point of the trip. We live in an "academically rigorous" school district, which really only has two meanings: they give a ridiculous amount of homework and they make the kids haul a ton of books back and forth to school each day. (Can't have lockers to store the books in, no sir, kids might put drugs in them, instead of in their backpacks where drugs belong!) We transport the kids as much as possible in an attempt to stave off future back problems. If they weren't carrying >30 pounds of books every day they could walk. In the same way, my wife could walk to the store and back, but the return trip with a week's worth of groceries might be a bit hard on her.

We have lived places where the store was just around the corner, and we did walk then, but this isn't one of those places.

 

[sethro_GT]

my miles per tank has increased about 50 since replacing the shot wheel bearings. I should get around 360 before the light comes on.

 

[slavrenz]

Sure, if just getting your body there and back was the only point of the trip. We live in an "academically rigorous" school district, which really only has two meanings: they give a ridiculous amount of homework and they make the kids haul a ton of books back and forth to school each day. (Can't have lockers to store the books in, no sir, kids might put drugs in them, instead of in their backpacks where drugs belong!) We transport the kids as much as possible in an attempt to stave off future back problems. If they weren't carrying >30 pounds of books every day they could walk. In the same way, my wife could walk to the store and back, but the return trip with a week's worth of groceries might be a bit hard on her.

We have lived places where the store was just around the corner, and we did walk then, but this isn't one of those places.

I hear ya there - it doesn't get much better in college